Workspace addressing system

ABSTRACT

The invention relates to a computer in which control means provide for high speed context switching. In a more specific aspect, the invention involves an arithmetic unit in which a workspace pointer register and control means operable on an interrupt store the contents of the workspace pointer in an element of a workspace in memory designated by the interrupt program and store in the workspace pointer register the address of the first element of the interrupt program workspace. 
     A first register stores the address of a first element of a set of dedicated workspace elements in main memory. 
     A second register stores the memory address of a current instruction of a problem program. 
     A third register maintains current the status of execution of the problem program of which said instruction forms a part; and 
     Workspace for the problem program is the set of workspace elements referenced by the contents of the first register, and upon occurrence of an interrupt, a new workspace is utilized to store the contents of the registers for the problem program permitting return to the problem program by shifting to the registers the contents stored in memory.

This is a continuation, of application Ser. No. 408,150, filed Oct. 19, 1973 now U.S. Pat. No. 3,944,985.

This invention relates to a general purpose digital computer and more particularly to structure providing flexibility in designating and utilizing workspaces in the main memory in the computer.

In prior computer systems, a main memory generally is employed for storage of instructions and data. In connection therewith, a register file normally has been provided for use as workspace and in general involved a transfer between the register file and memory of data and instructions.

In more recent systems such as represented by the computer manufactured and sold by Texas Instruments Incorporated of Dallas, Tex., and identified as Model 960-A Computer, provision has been made for addressing workspace as memory or as a register file. In that system, a counterpart of the register file is dedicated and fixed in memory. This imposes a measure of constraints on operation of the systems because all of the programs that use such workspace normally have to share the register file.

The present invention facilitates elimination of the constraints that are inherent in the systems of the above type in that contents of a workspace register designate the address of workspace in memory. Means are provided wherein the location of workspace is selectable by a programmer. Several such selected workspaces can be specified by the programmer and linked together for inter-program communication. Means are provided to shift the computer operation from one program to another at high speed with means to store the necessary information to shift back or return to an interrupted program at the point at which an interrupt occurred.

In Volume 2 of the Maintenance Manual for Texas Instruments 960-A Computer, FIGS. 3-4 illustrate an arithmetic structure wherein the location of a workspace in main memory is generated in a multiplexer by a 16 bit preset input and a register address. This register address has four bits that are available to be used to select one of 16 elements comprising the workspace. The bit number 8 in the preset input and the four bits in the R register address are employed so that the address generated selects an appropriate register in a fixed register file as the desired workspace element.

In accordance with the present invention, a workspace pointer register is provided in which the address of the first element of any selected set of memory locations can be loaded thereby to designate a workspace location in memory. In such operation, the set of elements thus designated is utilized in the execution of a problem program.

In accordance with the present invention, means are provided for high speed context switching, i.e., switching from one program or routine to another in the middle of the execution of a problem program. Means responsive to an interrupt stores the current contents of the workspace pointer register in a new workspace for return to the problem program when the program causing the interrupt is completed and provides sequencing means to load the address of the first element of the new workspace into the workspace pointer register. Upon return, the sequencer reloads the workspace register with the pointer address stored in memory.

More particularly, in accordance with the invention, a high speed context switching computer is provided in which a multi function arithmetic unit has two input buses with a first and second multiplexer connected to the input buses of the arithmetic unit. A workspace register is connected to one input of one of the multiplexers and the computer is provided with means to utilize a set of memory elements as first workspace for a current problem program with the address of the first of the elements corresponding to the contents of the workpiece register. Control means is operable upon occurrence of an interrupt to load the workspace register with an address of the first element of a second workspace in memory for use by the interrupt program and for storing in a predetermined element of the second workspace the address of the first element of the first workspace. The program counter register is connected to one of the multiplexers to maintain the address of the current instruction in the problem program. The control means stores the contents of the program counter in a predetermined element of the second workspace upon occurrence of an interrupt.

The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as further objects and advantages thereof, will be best understood by reference to the following detailed description of an illustrative embodiment, when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram providing an overview of a computer employing the present invention;

FIG. 2 is a more detailed block diagram of the computer of FIG. 1;

FIG. 3 illustrates operation of special registers in initial operations employing main memory as workspace;

FIG. 4 illustrates the effects of an interrupt subroutine on the operation of the special registers;

FIG. 5 illustrates portions of the central processing unit;

FIG. 6 is a more detailed illustration of the operations of FIG. 5;

FIGS. 7, 8 and 9 are flow diagrams illustrating operations involving workspace and memory;

FIG. 10 illustrates the A multiplexer of FIGS. 8 and 9;

FIG. 11 illustrates the B multiplexer.

FIG. 1

The computer described herein represents a combination of elements well suited for environments that require a large number of program context changes at high speed. Very rapid context switching results directly from use of a special register for holding the current workspace address. An efficient memory to memory architectural structure employing two address instructions, standard multiply and divide hardward plus standard priority vectored interrupts is provided. Further, it provides standard features which allow user substitution of hardware modules for certain software routines. Bit, byte and word addressing may be utilized. Single, double and triple word instructions are included.

The basic structure of the system is illustrated in FIG. 1 wherein a central processing unit (CPU) 10 includes an arithmetic unit (AU) 12 and a control ROM 14 which in one embodiment comprises 256 words of 64 bits each. An automatic load ROM 16 is also connected to the arithmetic unit. A communication bus controller master 18 provides for interchange of data and instruction with outside memory by way of a bus 29. An interrupt priority encoder 20, a console interface 22 and a communication register unit (CRU) interface 24 are provided for communicating with units outside CPU 10.

The bus controller master 18 communicates with a memory 26 as well as to other peripherals 28 over bus 29. The encoder 20 receives signals from outside equipment designated by the reference character 30. In addition, the encoder 20 responds to signals from the AU 12 for generating interrupts dependent upon internal operations in the AU 12.

Interface 22 is connected for communicating with a console 32. Interface 24 is provided for communicating with external units such as unit 34. Communication by way of the master 18 is high speed communication. The communication through interface 24 is low speed communication.

The embodiment of the invention here described employs 16 bit data words and 20 bit addresses. AU 12 preferably comprises all electronics necessary to acquire and execute instructions from memory and to perform input/output operations. Special registers are provided which have specific and defined uses. Workspace elements are all located in memory and are employed in connection with use of the special registers. The special registers are three in number. They are 16 bit registers. The first is a workspace pointer hereinafter referred to as WP. The second is a program counter hereinafter referred to as PC. The third is a status register hereinafter referred to as ST. The PC and WP always contain an even address. Workspace pointer, WP, contains the address of the first of 16 consecutive memory locations that are actively used as workspace elements.

The program counter, PC, contains the address of the current instruction being executed at any given time. The status register, ST, contains the information shown in Table I as to the state of CPU 10.

                  TABLE I                                                          ______________________________________                                         0    1      2     3   4   5   6    711      12 15                              ______________________________________                                              A      E     C   O   O   X   Reserved  Interrupt                          LT   LT     Q     A   V   D   O   for MEM    Mask                              GT   GT           R   F   D       MAP FILE                                                       R           P   and inter-                                                     Y       P       rupt mask                                                                      expansion                                    ______________________________________                                    

CONDITION CODE BITS Bit 0.

Bit 0 is set to a logic "1" as an indication of a Logical Greater Than condition. This comparison test is enabled during certain compare instructions. The test is also enabled to compare the result of a double or single operand instruction with zero. When any test fails, bit 0 is reset.

Bit 1

Bit 1 is set to a logic "1" as an indication of an Arithmetic Greater Than condition. This comparison test is enabled during the same compare instructions as for bit 0. The test is also enabled to compare the result of a double or single operand instruction with zero. When any test fails, bit 1 is reset.

Bit 2

Bit 2 is set to a logic "1" as an indication of an Equal condition. The comparison test is enabled during the same compare and during corresponding bit instructions. The test is also enabled to compare the result of a double or single operand instruction with zero. When any test fails, bit 2 is reset.

Status bit 2 is also set when a CPU bit is tested with a test bit (TB) instruction and the CRU bit equal to a logic "1." Bit 2 is reset if the CRU bit is a logic "0."

Bit 3

Bit 3 indicates a carry out from the most significant bit position of an arithmetic operation result. Bit 3 may be loaded during add, subtract, increment, or decrement instructions. The carry indicator is also loaded with the carry out from the most significant or least significant bit position of shift operands. The carry will indicate the last incremental shift performed.

Bit 4

Bit 4 indicates Arithmetic Overflow and is reset when no overflow occurs. Bit 4 is affected during add, subtract, increment and decrement instructions. Overflow occurs when the result of an arithmetic operation cannot be correctly represented with a 16 bit signed two's complement value.

Bit 5

Bit 5 is set to indicate the parity of the last byte operand or resulting byte of a byte instruction. It is set to a logic "1" when the last byte operand contained an odd number of bits, otherwise it is reset.

Bit 6

Bit 6 is set to a logic "1" by the execution of an extended operation (XOP) instruction. It indicates that an extended operation is in progress. This bit can be reset by program control.

Bits 7 through 9

Bits 7 through 9 are made available for use in memory mapping. For the purpose of this description these bits will always contain zeros.

Bits 10 and 11

Bits 10 and 11 are available for interrupt mask expansion.

In this embodiment, bits 7-11 are all zeros.

Bits 12 through 15

Bits 12 through 15 are used to indicate the interrupt mask level. The four bit value in this field specifies that level and those of higher priority which are enabled as indicated in Table II.

                  TABLE II                                                         ______________________________________                                         ST12 ST13   ST14   ST15                                                        ______________________________________                                         0    0      0      0    Interrupt level zero only                                                      enabled                                                0    0      0      1    Interrupt level one and                                                        above enabled                                          0    0      1      0    Interrupt level two and                                                        above enabled                                          .    .      .      .      .                                                    .    .      .      .      .                                                    .    .      .      .      .                                                    1    1      1      0    Interrupt level fourteen                                                       and above enabled                                      1    1      1      1    All interrupt levels enabled                           ______________________________________                                    

An important and significant difference in the computer of the present invention and prior systems lies in the provision of the workpiece pointer WP. The program counter PC and the status register ST are used in a conventional sense. Together the WP, PC, ST registers are so employed to lend versatility in context changing operations when processing control is shifted from one program to another as may be requested or directed in response to interrupt signals, to commanded subroutine linkages or in carrying out of extended operations (XOP).

The AU 12 responds to instructions to process data in accordance with a method of utilizing a workspace at a selectable location in memory. Workspace heretofore has been provided in a single fixed register file or multiple fixed register files with system design such that context switching requires that some portion of the register file be stored and reloaded in order to achieve a context change. A corresponding length of time is required to return to a prior program context because the register file must generally be restored to prior values. Both the initial contexxt change and the time to return to a prior program has been long compared to that involved in the present invention. The reason for improvement achieved by the present invention is that all that is necessary for a context change is to store and load the contents of three registers. Return to a prior program requires only that three registers be loaded with prior contents.

In the embodiment of the present invention, memory 26 consists of a printed circuit card which in total may store 4,096 16-bit words plus parity. Metal oxide semiconductor (MOS) integrated circuit networks preferably are employed as storage elements to provide for high speed memory operations. Such memory card additionally contains all address and data logic, control and timing logic and level converters to interface to a communication bus leading to AU 12.

The workspace in memory 26 is configured as shown in Table III.

                  TABLE III                                                        ______________________________________                                                       0                                                                              1                                                                              2                                                                              3                                                                 ##STR1##        4 Work space elements- may contain Data or Addresses 5 6                       8 9  10                                                                       11                                                                    CRU Base 12 CRU Base                                                           Stored WP                                                                               13 Address of Prior                                                            Program Workspace                                                     Stored PC                                                                               14 Address of next                                                             instruction word                                                               in prior program                                                      Stored ST                                                                               15 Status at the                                                               time WP and PC                                                                 Linkage Data                                                                   was stored                                                     ______________________________________                                    

The workspace pointer WP defines the first element in the active set of workspace elements shown in Table III. Workspace elements are numbered EO through E15 and can exist anywhere in memory 26 as a group of 16 consecutive memory word locations. The special addresses for storing linkage data in workspace shown in Table III are generated by arithmetically addressing the contents of the WP register to a partial address. The prior contents of the WP register are then stored at the address in memory corresponding to the resultant sum, i.e., element 13 of the workpiece shown in Table III.

As seen from Table III each workspace set comprises 16 words or elements, 0-15. The first element is specified by the address in the WP. The element actually selected is specified by the sum of the address in WP and an additional component obtained from an address field in a computer instruction. This component is added to the contents of WP. Thus the 16 locations of the workspace are all directly addressable by certain computer instructions and the workspace can be moved to any location in memory by changing the value in WP. Location 11 is employed in some instructions as an address storage location. Element 12 is employed as CRU base storage for instructions that apply to the use of CRU. In context changing operation Element 13 in the new program workspace always is employed to store the address of the prior program workspace. Element 14 in the new program workspace always stores the address of the next instruction in the prior program. Element 15 in the new program workspace always stores the status of the program being executed at the time the WP and PC linkage data was stored.

FIG. 2

AU 12 FIG. 1 has been shown in greater detail in FIG. 2 in conjunction with the autoload ROM 16 and the interrupt priortiy encoder 20. The system includes a workspace pointer (WP) register 40, a status register (ST) 41 and a program counter (PC) 42 which operates in conjunction with an arithmetic logic unit (ALU) 43 under suitable control as to permit designation of workspace in memory 26, FIG. 1. Memory 26, FIG. 1, is connected to the AU 12 by way of a high speed bus 29 which operates to permit various master devices to exchange information with slave devices such as memory 26.

AU 12 utilizes 16 elements of memory as workspace. The starting address of such workspace in memory is contained in the register 40. As will be shown, a plurality of such workspaces can be designated in order to permit the execution of a plurality of different programs while retaining all information necessary to return to interrupted or prior programs and continue execution thereof.

Returning again to FIG. 2, data from memory is applied by way of a 16 bit bus 44 and by way of a gating unit 45 to an A-bus multiplexer 46. The output of multiplexer 46 is applied by way of an A input circuit 47 to the ALU 43. The data bus 48 also leads to a shift register 49, to workspace pointer 40, to a memory data (MD) source buffer register 50, to a destination address buffer 51 and to an instruction decoder 52.

WP register 40, PC register 42, shift register 49 and MD source buffer register 50 are each connected to a B-bus multiplexer 53 and thence, through an input circuit 54, to the B input of ALU 43. The output of ALU 43 is connected to PC register 42, shift and destination register 55, to a bus address counter 56 and to a bus write data register 57.

The autoload ROM 16 is connected to register 57. The output of write data register 57 is connected by way of a 16 bit bus 58 to the bus 29 and by way of a bus 59 to a communication register unit control 60, the output of which is applied to a communication register unit interface unit 24. An instruction decoder 52 is connected at its output to the control unit 14 which in turn is connected to the CRU control unit 60. Instruction decoder 52 is also connected to the interrupt priority encoder 20. Control unit 14 is also connected to one input of the A input circuit 47 and to the B input circuit 54. Shift and destination register 55 is connected to one input of multiplexer 46. The destination address buffer 51 is connected to two inputs to multiplexer 46. One of the inputs has two 8 bit bytes presented in normal order and the other has two 8 bit bytes in reverse order.

Interrupt priority encoder 20 is connected to the status register 41 whose output is then connected to multiplexer 46. Interrupt priority encoder 20 also is connected directly by one output of multiplexer 46. A line 61 from TILINE bus applies a time out state to the encoder 20. A line 62 applies a memory parity bit to encoder 20. Equipment interrupts are applied by way of a 10-line bus 63 to the interrupt priority encoder 20. The output of TILINE bus address counter 56 is connected to the input of autoload ROM 16 whose output is connected to one input to write data register 57. Address counter 56 is provided with an automatic increment facility as indicated by the line 64. Similarly, program counter 42 is provided with automatic increment capability as indicated by the line 65.

FIG. 3

The foregoing description provides an overview of the computer system embodying the present invention. In providing flexibility in designating and using workspace, the WP register 40, ST register 41 and PC register 42 play significant roles as illustrated in FIG. 3.

In initialization of the system, the autoload ROM 16 has stored in the first element thereof the address of the first element of the workspace to be employed in memory. The second element of ROM 16 has the address of the first instruction in the program to be first executed by the computer upon startup. The rest of the elements of ROM 16 are available for the programmer to utilize as necessary for initialization purposes. It will contain the initialization program and in the present embodiment may comprise as many as 256 16 bit words.

Upon startup, the entire contents of the ROM 16 are transferred to occupy the first 256 elements of memory 26. Thus, the WP and PC addresses are stored in the first two elements of memory 26.

After transfer of the contents of ROM 16 to memory 26 the WP address is transferred from the first element of memory 26 to WP register 40 and the contents of the second element of memory 26 to PC register 42 and execution of initialization program begins as a result of the initialization process. One or more programs to be executed by the computer may then be loaded into memory 26. Thereafter, the initialization program in memory 26 may replace the WP address in register 40 with a new WP address and will replace the PC address in register 42 with the address of the first instruction of a problem program.

In FIG. 3 the initialization program workspace is indicated as memory space 70. The problem program workspace is indicated as the memory space 71 with the problem program occupying memory space 72. The WP register 40 contains the address of the problem program workspace and the PC register 42 contains the address of the next problem program instruction. In this condition, the computer will then proceed to execute the problem program with the program counter being incremented or changed as directed for each instruction in memory and the address in the WP register 40 remaining constant or undergoing change in response to instructions contained in the program as may be directed at the initiative of the programmer preparing the problem program. ST register 41 will change contents as to maintain a current indication of the status of the execution of the problem program. The latter function of status registers is well-known. ST register 41 operates in a manner corresponding in all essential respects with the operation of the status register in the Computer 960-A above identified.

FIG. 4

In FIG. 4 the operation of the registers 40-42 of FIG. 3 is illustrated when an interrupt occurs during the execution of a given problem program. In the illustration of FIG. 4, memory 26 has stored therein a first problem program in memory space 73 and operates in conjunction with a problem program workspace 74.

For each interrupt that may be required in operation of the computer, the WP address of the first element of the workspace for that interrupt is stored at a programmed location in the first set of 64 locations in memory 26 by writing over any initialization program at the desired memory locations for the interrupt data, since once the initialization program has been employed in startup, the space is then available for use in other operations.

Similarly, for each interrupt, the PC address of the first instruction in the interrupt subroutine is stored in one of the elements of the first 64 elements of memory storage. In FIG. 4, element 75 is illustrated as the site for storage of the workspace pointer WP for a subroutine and element 76 is indicated as the site for storage of the program counter PC address, namely the address of the first instruction in the interruupt subroutine.

Upon occurrence of an interrupt, the computer automatically transfers from the problem program in memory space 73 operating in conjunction with workspace 74 to the interrupt subroutine 78 operating in conjunction with workspace 77. This is accomplished as follows: The contents of WP register 40 are transferred into the interrupt subroutine workspace 77 along with the contents PC of program counter 42 and the contents ST of status register 41. The contents of elements 75 and 76 are then transferred to registers 40 and 42, respectively. Concurrently, the computer changes the interrupt mask in the status register 41 to mask any lower priorty interrupts so that the subroutine will run to completion unless a higher priority interrupt occurs. Thus the next instruction processed is in the interrupt subroutine 78.

Upon completion of the interrupt subroutine which is stored in memory at location space 78, the subroutine executes a return command in which event the WP address, the PC address and the contents ST of status register 41 that were stored in the interrupt subroutine workspace 77 are replaced into registers 40, 42, and 41, respectively, and the computer then return to operating on the problem program at the same point it was at upon the occurrence of the interrupt.

FIGS. 5 and 6

Referring now to FIGS. 5 and 6, the ALU 43 is shown in its operative relation with respect to the A-bus multiplexer 46 and the B-bus multiplexer 53. The A-bus multiplexer 46 has eight inputs. The B-bus multiplexer 53 has four inputs. ALU 43 may comprise four LSI chips of the type described in TTL Data Book For Design Engineers by Texas Instruments Incorporated, Dallas, Tex. 1973, page 381, and identified as TI Arithmetic Logic Unit/Function Generator SN74181, to form a 16 function arithmetic logic unit. Unit 43 is the same type as employed in the Computer 960-A above identified and thus will not be detailed here.

The arithmetic unit 43 has an output bus 43a which leads to an address register (ADC) 56. Line 43a also leads to the input of a multiplexer C whose output leads by way of a transmitter bank 96 to the data bus 29b leading to memory. Bus 29b is a two-way bus. Bus branch 29c leads back to a receiver bank 97 to supply data to the CPU. In addition, register 56 has an output line 29a which feeds the output data to the bus 29 leading to memory.

In FIG. 5, a first input on line 80 is applied to multiplexer 46 by way of a subsidiary multiplexer 46a. The trap address input appears on bus 80 and is the address in memory at which is stored the workspace pointer value of the workspace pointer for the interrupt of highest priority, and is derived from interrupt priority encoder 20, FIG. 2.

A second input is from a memory bus at the output of receiver 97 and appears on line 81 which leads to a buffer register 82. The TD field in register 82 is the tag field for the destination address which is contained in the D field. The D field as it appears on bus 83 is shifted left two spaces and has added thereto a constant, the hexadecimal 40, in order that the address applied through the multiplexer 46a will properly identify the location in memory of the workspace pointer for the extended operation identified in the D field of register 82.

A third input on line 83a is applied from the D field, shifted left by one space thereby multiplying the same by 2, to provide the word address of the destination element in workspace. This is applied by way of auxiliary multiplexer 46b.

The next input is derived by way of a memory bus 84. This input is the source address shifted one space left to provide a word address of the source element. It is applied to ALU 43 by way of the auxiliary multiplexer 46b and multiplexer 43.

The next input is the output of the status register 41 appearing on bus 85 and is applied directly to the multiplexer 46.

The next input is on bus 86 and is employed for purposes not significant to the present description.

The next input is on bus 87 which is data read from memory. Data on bus 88 is read from memory with the byte order reversed.

The next input appears on the ALU output bus 43a and is applied to a utility register 90 (URA) which serves to buffer output data from the ALU 43.

The last input to the multiplexer 46 is by way of bus 81 through utility shift register 91 (URB) which is connected to output bus 92. The latter is also applied as the first input to multiplexer 53.

The workspace pointer register 40 is connected at its input to the memory bus 81 and at its output to the multiplexer 53.

Memory bus 81 is also connected through memory data buffer register 94 to multiplexer 53. Finally the output of the ALU 43 is connected by way of bus 43a to the PC register 42 the output of which is connected to the multiplexer 53.

In the present invention, arithmetic logic unit 43 provides an output which is buffered in the memory address register 56. At any given time in the course of operation of the computer where memory is to be accessed, the memory location will be specified by a code stored in register 56.

In accordance with the present invention the workspace is specified by utilizing the programmable contents of WP register 40 which is connected to multiplexer 53 and applied to ALU 43. A particular element in the workspace is addressed by the contents of register 56, which is determined by the value of the address from WP register 40, and an address either from the bus 84 or buffer 82 which is transmitted by way of multiplexer 46b and multiplexer 46 to ALU 43. In ALU 43 the contents of register 40 and the address on bus 84 are summed so that the address of the desired element of the workspace is then specified by the contents of register 56. Likewise the address from buffer 82 can be summed with WP register 40 to obtain a workspace element address.

FIGS. 7-9

FIGS. 7, 8, and 9 comprise a flow diagram which illustrates operation such as represented by the initialization functions of FIG. 3 and the interrupt functions of FIG. 4 with the return to the problem program after an interrupt. The flow diagram of FIGS. 7, 8 and 9 should be considered in connection with the system diagrams of FIGS. 5 and 6.

In the flow diagram of FIGS. 7-9 the computer states involved are indicated by a block, such as block 99, FIG. 7. The particular state is identified by the signature in the upper right hand corner of such block. Block 99 for example represents state FF as coded in hexadecimal notation. The computer has 256 states, as will be shown, of which only 18 states are directly involved in FIGS. 7-9. In each state several steps or conditions are effective. The conditions are simultaneous and occur in response to a high speed clock in Control ROM 14.

Beginning in FIG. 7 at MRESET 101, master system reset, memory data line 81 of FIG. 5 is cleared to zero input. Proceeding into state FF, the ALU 43 is cleared for a zero output. The memory address register 56 and program counter register 42 are then loaded from the ALU for a zero input. The status register 41 and workspace pointer register 40 are loaded from memory data line 81 for a zero input. After checking to see if the reset operation is complete, the computer operation then shifts to state FO where data in memory is fetched from the address reflected by the contents of memory address register 56. As the register contains zeros, the contents of the first memory location will appear at the memory bus 81. The address of the first element of the initial workspace is contained in the first word in memory.

The computer operation then proceeds to state 20 of FIG. 8. The memory data register 56 is incremented to reflect the address of the second word in memory, which contains the address of the first program instruction to be executed. The contents of the workspace pointer register 40 are then placed at the output of the ALU. At this point in time the ALU output is zero. The workspace pointer register is then loaded from memory bus 81 of FIG. 5 to contain the address of the first element of the initial workspace. Utility register A is loaded from ALU to contain zeros. Data is then fetched from the address reflected in the memory address register 56, which is the address of the second word in memory. The data, the address of the first program instruction to be executed, appears on the memory bus 81.

The computer checks to see if the fetch cycle is complete, and if so it proceeds to state 50. The address of the first element in the initial workspace is summed with the value 13 in the ALU. The address of the 13th element in the workspace is thus made to appear at the output of the ALU. The memory address register 56 is then loaded with the output of the ALU, and utility register B is loaded from memory to contain the address of the first instruction to be executed. The computer checks to see if the function of state 50 has been completed, and if so proceeds to state 52 if Restart is not required.

In state 52, the contents of the utility register A are made to appear at the output of the ALU. The output of ALU 43 in this case is zero, the address in memory which contains the address of the first element in the initial workspace. The ALU output, the initial contents of the workspace pointer register, is then stored in the address in memory reflected by the current contents of memory address register 56. The output is thus stored in the thirteenth workspace element of the initial workspace. The memory address register is then incremented to reflect the address of the fourteenth workspace element in the initial workspace. After checking to see if the store cycle is complete, the computer operation shifts to state 90.

In state 90, the contents of the program counter register 42 is placed at the output of the ALU 43. The ALU output, the initial content of the program counter register 42, is then stored in the fourteenth workspace element of the initial workspace. The address of the 14th element is contained in the memory address register 56. The memory address register is then incremented to reflect the address of the fifteenth workspace element in the initial workspace. After checking to see whether the store cycle is complete, the computer operation proceeds to state 91.

In state 91, the contents of status register 41, are made to appear at the output of ALU 43. The ALU output, the initial contents of the status register, are then stored in the address reflected by the contents of the memory address register 56. The output is thus stored in the 15th workspace element of the initial workspace. The computer checks to see if the store operation is complete and then proceeds to state 92.

In state 92, the contents of URB 91, the address of the first instruction to be executed, are placed at the output of the ALU. The memory address register 56 and the program counter register 42 are then loaded with the ALU output. The first instruction to be executed is then fetched from the memory address contained in the memory address register and appears at memory data bus 81. An end of instruction completes the state 92 operation. The computer proceeds with the instruction acquisition state 22, checks to see if the fetch cycle is complete, and then continues into state 1E, FIG. 9.

At this point it will be assumed that the operation is to load the autoload ROM contents into the first 256 memory elements. In state 22, the system acquires the necessary instruction. Following completion of a fetch step, the operation shifts to state 53.

In step 1, zeros are applied to the input of the ALU. In step 2, the address register is loaded with zeros. The operation then shifts to state BB. In step 1, a loader between ROM 16 and memory is enabled. The 256 words from ROM 16 are then sequentially stored in the first 256 elements of memory. This is done, as in step 4 of state BB, wherein the address register is sequentially incremented.

A store step is looped back to state BB. An inquiry as to whether or not the autoload ROM address is at a maximum (256) is also involved in a succeeding step which is looped back to state BB. When all the instructions in the autoload ROM 16 have been loaded into memory, then the operation shifts to state BA. In this state, zeros appear at the output of the ALU. Following this, the operation then shifts to state 20 wherein the operations above-described follow.

Assume now that a problem program is to be interrupted. The vectored priority interrupt system is enabled or disabled by computer instruction. Typically one instruction is to enable an interrupt of given level and those of higher priority. With the system in the operating mode and the CPU operating on a problem program, an interrupt controller is actuated and the CPU is forced to state 00, FIG. 7. In the step 1 of state 00, the trap, the address to which the program is directed in the interrupt, is applied to the input of an E multiplexer 46a FIG. 5.

In step 2, the output of the E multiplexer is applied to the A input of the ALU. In step 3, the A input appears at the output of the ALU. In step 4, the address register load is enabled and in step 5, the fetch command is issued. This serves to put the address of the new WP into the memory address register.

The operation then shifts to state 28 where in step 1 the address register is incremented. In step 2 the WP is applied to the B input terminal of the ALU, and in step 3 appears at the output of the ALU. In step 4, the WP register load is enabled to load the new WP address into register 40. In step 5 the utility register A load is enabled to save the old WP in the utility register A. In step 6 a fetch command is issued.

After the fetch is completed, the operation shifts to state 50, FIG. 8, and from there the operation proceeds to state 92 to the end of instruction as previously described.

The system then operates through the interrupt subroutine and when it comes to the end of the subroutine of the interrupt, a return signal is produced instructing the system to return to the point in the problem program at which the interrupt occurred. In state IE, step 1, the address 13 in the workspace applied to the A input terminal of the ALU appears at the output of the ALU. In step 2, the WP address is applied to the B input of the ALU. In step 3, the two inputs are then added and appear at the output of the ALU. In step 4, the address register load is enabled and a fetch is called for in step 5.

The operation then shifts to state CC which loads the WP register 40 with the old WP previously stored in memory. In step 1, WP register 40 load is enabled. In step 2, the address register is incremented to generate the address of the old PC, and in step 3 fetch is called for.

When the fetch is completed, the program shifts to state 56. In step 1, the PC address that was stored in memory is applied to the A input of the ALU in route to the PC register 42. In step 2, the A input appears at the output of the ALU. In step 3, the PC register load is enabled. In step 4, the address register is incremented to form the address of the status ST previously stored in memory. In the final step, the fetch is requested.

When the fetch is completed, the program shifts to state 58 which signals an end of instruction. In step 2, the old ST is loaded into the status register. In the next three steps, there is an update in memory of the address of the PC. More particularly, the PC appears at the B terminal of the ALU and in the next step appears at the output thereof and then is stored in the address register. A fetch is then called for. The program then proceeds to state 22 where the computer will now take up operation in the old program where the interrupt occurred.

As shown in FIG. 6, the output bus from multiplexer 46 is a 16 line bus. The output from the multiplexer 53 similarly is a 16 line bus. The output from the ALU 43 similarly is a 16 line bus 43a. The control ROM 14 supplies four lines 14a to multiplexer 46 and three lines 14b to multiplexer 53. The four lines 14c lead to the ALU 43. A decoder 43b is connected to lines 14a and has outputs connected to NAND gates 46c, 46d, 46e and 46f. NAND gate 46c is connected to the next to the least significant bit line leading from multiplexer 46. NAND gates 46d, e and f are located in successively more significant bit lines leading to the A input of the ALU 43. In a similar manner, the decode unit 53b is connected at its output through a NAND gate 53c which is in the next to the least significant bit line in the bus leading from multiplexer 53.

The control unit 14 is a read only memory comprising eight LSI chips on which the word pattern is formed as set out in the following Table IV. It will be recalled that the memory comprises 256 words of 64 bits each.

The state column in Table IV tabulates numerical designation of the states in which the computer operates. For example, line 1 designates states 0-3. Line 2 designates states 4-7. The last line designates states 252-255. Column 1 of the word patterns indicates the states of the first eight bits of the output word of ROM 14 when the computer is in state 0. Column 2 of the word patterns indicates the states of the first eight bits of the output of ROM 14 when the computer is in state 1. Column 3 indicates the states of the first eight bits from ROM 14 when in state 2. Column 4 indicates the states of the first eight bits from ROM 14 in state 3.

In Table IV (2) the same information is set out for the second eight bits of the memory words. In Table IV (3) the states of the third set of eight bits are set out. There are five additional Tables IV (4) - IV (8). Thus, the state of every one of the 64 × 256 bits in the ROM 14 are signified in Table IV to provide control for each of the 256 states.

ROM 16 configured as indicated in Table IV (1-8) is employed to provide output control for the various elements of the AU 12 shown in FIGS. 5 and 6 as well as elements not shown as not pertinent to context switching operations.

As indicated in FIG. 1, the control ROM 14 is addressed by an eight bit bus with a 64 bit word being produced by the control ROM 14 for each of 256 states. The present description directs attention to the use of the control ROM 14 to implement the selective location in memory of workspace.

                                      TABLE IV                                     __________________________________________________________________________     WORD PATTERN                                                                   STATE COL. 1  COL. 2  COL. 3  COL. 4                                                 87654321                                                                               87654321                                                                               87654321                                                                               87654321                                         __________________________________________________________________________     0-3   HLLHLLLH                                                                               HLLHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         4-7   HLHLHHLL                                                                               LLHHHLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                          8-11 LLHHLLLL                                                                               LLHHLLLL                                                                               LLHHLLLL                                                                               HHHHHLLL                                         12-15 HHHHLLLL                                                                               LLHHLLLL                                                                               HHHHLLLL                                                                               HHHHLHLL                                         16-19 HHHHHLLL                                                                               HHHHHLLL                                                                               HHHHHLLL                                                                               HLHLHHLL                                         20-23 HHHHHLLL                                                                               LHHLLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         24-27 HLHLHHLL                                                                               HLHLHHLL                                                                               LLHHLLLL                                                                               HLHLHHLL                                         28-31 HHHHHLLL                                                                               HHHHLLLL                                                                               LLHLLLLL                                                                               LLHHLLLL                                         32-35 HHHHLLLL                                                                               HHHHLLLL                                                                               LHLHLLLH                                                                               LLHHHLLL                                         36-39 HHHHHLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               LLHHLLLL                                         40-43 HHHHLLLL                                                                               HHHHLLLL                                                                               LLHHHLLL                                                                               HHLHLLLL                                         44-47 LLHHLLLL                                                                               HHHHLHLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         48-51 HHHHLLLL                                                                               LLHHLLLL                                                                               LLHHHLLL                                                                               HHHHLLLL                                         52-55 HHHHHLLL                                                                               HHHHHLLL                                                                               HHHHHLLL                                                                               HLHLHLLL                                         56-59 LLHHLLHL                                                                               LLLHHLHL                                                                               HHLLLLLL                                                                               HHHHHLLL                                         60-63 HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         64-67 HLHLHHLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         68-71 HLHLHHLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                         72-75 HLHLHHLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                         76-79 HLHLHHLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                         80-83 LLHHLLLL                                                                               HLHLHHLL                                                                               LLHHLLLL                                                                               HHHHLLLL                                         84-87 HHHHLLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                         88-91 HHLLHHLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                         92-95 HHHHLHLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                         96-99 LHLHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         100-103                                                                              LHLHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         104-107                                                                              HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         108-111                                                                              LLHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         112-115                                                                              LHHLLLLL                                                                               LHHLLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         116-119                                                                              HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         120-123                                                                              HHHHLLLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                                                               HLHLHHLL                                         124--27                                                                              HLHLHHLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                                                               HLHHLLLL                                         128-131                                                                              HHLHLLLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                         132-135                                                                              HLHLHLLL                                                                               HHHHHLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                         136-139                                                                              HHHHHLLL                                                                               HLHLHLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         140-143                                                                              HHHHHLLL                                                                               HLHLHHLL                                                                               LLHHLLLL                                                                               LLHHLLLL                                         144-147                                                                              HHHHHHLL                                                                               HLHHLLLL                                                                               HHHHLHLL                                                                               HHHHLLLL                                         148-151                                                                              HHHLHLLL                                                                               LHHHHLLL                                                                               HLHLHHLL                                                                               LLHHLLLL                                         152-155                                                                              HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         156-159                                                                              HLHLHHLL                                                                               HHHHLLLL                                                                               HHHHHLLL                                                                               LLHHHLLL                                         160-163                                                                              LLHHHLLL                                                                               HHHHLHLL                                                                               LLHHHLLL                                                                               LLHHHLLL                                         164-167                                                                              LLHHHLLL                                                                               LLHHHLLL                                                                               LLHHHLLL                                                                               LLHHHLLL                                         168-171                                                                              LHLHLLLL                                                                               LLHHHLLL                                                                               LLHHLLLL                                                                               HLHLHLLL                                         172-175                                                                              HHHHLLLL                                                                               HHHHLHLL                                                                               HHHHLLLL                                                                               LLHHHLLL                                         176-179                                                                              HHHHHLLL                                                                               HHHLLLLL                                                                               LLHHLLLL                                                                               HLLHLLLL                                         180-183                                                                              HHHHLLLL                                                                               HLHLHLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         184-187                                                                              HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHHLLL                                         188--191                                                                             HLHLHLLL                                                                               HHHLHLLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                         192-195                                                                              HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHHLLL                                         196-199                                                                              HHHHLLLL                                                                               LLLHHLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                         200-203                                                                              LLLHHLLL                                                                               HHHHLLLL                                                                               HLHLHHLL                                                                               HHHHLLLL                                         204-207                                                                              HHHHLLLL                                                                               LLHHHLLL                                                                               LLHHLLLL                                                                               HHHHLLLL                                         208-211                                                                              HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         212-215                                                                              HHHHHHLL                                                                               LLLHHHLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                         216-219                                                                              HHHLLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               LLHHLLLL                                         220-223                                                                              HHHHHHLL                                                                               HHHHLHLL                                                                               HHHHLLLL                                                                               HHHLHLLL                                         224-227                                                                              HHHHLLLL                                                                               LLHHLLLL                                                                               HHHHLHLL                                                                               LLHHLLLL                                         226-231                                                                              HHHHLLLL                                                                               HHHHHLLL                                                                               HHHLLLLL                                                                               HHHLLLHL                                         232-245                                                                              HHHHLLHL                                                                               HLHHLLLL                                                                               LHHHHLLL                                                                               LLHHHLLH                                         236-239                                                                              HHHHHLHL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HLHLHLHL                                         240-243                                                                              HHHLLLLL                                                                               HHHHLLLL                                                                               HHHHLLLL                                                                               HLHHHLHH                                         244-247                                                                              HHLLHLLH                                                                               HHHHHHLL                                                                               HHHHLLLL                                                                               HHHHHLLL                                         248-251                                                                              HLHLHHLL                                                                               HHHHLLLL                                                                               HHHHHHLL                                                                               HHHHHLLL                                         252-255                                                                              HHHHLLLL                                                                               HHHHHLLL                                                                               HHHHLHLH                                                                               HHHHLLLH                                         C-3   LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         4-7   LLHLLHLL                                                                               LLHLLHHH                                                                               LLHLLLLL                                                                               LLHLLLLL                                          8-11 LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                         12-15 LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLHHLH                                         16-19 LLHLHHLH                                                                               LLHLHLLH                                                                               LLHLHHLH                                                                               LLHLLHLL                                         20-23 LLHLHHLH                                                                               LLHLLHLL                                                                               LLHLHLLH                                                                               LLHLLLLL                                         24-27 LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                         28-31 LLHLHHLH                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         32-35 LLHLHHLH                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLHLL                                         36-39 LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         40-43 LLHLHHHH                                                                               LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                         44-47 LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                                                               LLHLLLLH                                         48-51 LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLHHHH                                                                               LLHLHLLH                                         52-55 LLHLLLLH                                                                               LLHLHLHL                                                                               LLHLLHLL                                                                               LLHLLHLL                                         56-59 LLHLLLHH                                                                               LLHLLLHH                                                                               LLHLLHLL                                                                               LLHLLLHH                                         60-63 LLHLLLLH                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         64-67 LLHLLHLL                                                                               LLHLHLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         68-71 LLHLLLHL                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         72-75 LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         76-79 LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         80-83 LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLHLLH                                         84-87 LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                         88-91 LLHLHHLH                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                         92-95 LLHLHHLH                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                         96-99 LLHLLHLL                                                                               LLHLLLLL                                                                               HLHLLLLL                                                                               LLHLLLLL                                         100-103                                                                              LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         104-107                                                                              LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                                                               LLHLLLLL                                         108-111                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         112-115                                                                              LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLHHLH                                         116-119                                                                              LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                                                               LLHLHHLH                                         120-123                                                                              LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLHLL                                                                               LLHLLHLL                                         124-127                                                                              LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                         128-131                                                                              LHHLLLLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         132-135                                                                              LLHLLHLL                                                                               LLHLHHLH                                                                               LLHLLHLL                                                                               LLHLLLLL                                         136-139                                                                              LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         140-143                                                                              LLHLHHLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         144-147                                                                              LLHLHHLL                                                                               LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                         148-151                                                                              LLHLLLLH                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         152-155                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         156-159                                                                              LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLHHLH                                                                               LLHLLLHH                                         160-163                                                                              LLHLHLHH                                                                               LLHLHHLH                                                                               LLHHHLHH                                                                               LLHHLLHH                                         164-167                                                                              LLHHLLHH                                                                               LLHHLHLL                                                                               LLHHHHLH                                                                               LLHHHHHH                                         168-171                                                                              LLHLLHLL                                                                               LLHLLLHH                                                                               LLHLLLLL                                                                               LLHLLHLL                                         172-175                                                                              LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                                                               LLHLLLHH                                         176-179                                                                              LLHLHHLH                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         180-183                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         184-187                                                                              LLHLHHLH                                                                               LLHLLHLL                                                                               LLHLHLLH                                                                               LLHLHHLH                                         188-191                                                                              LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                         192-195                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         196-199                                                                              LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         200-203                                                                              LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                         204-207                                                                              LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         208-211                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                         212-215                                                                              LLHLHHLH                                                                               LLHLLHLL                                                                               LLHLLLLL                                                                               LLHHHHHH                                         216-219                                                                              LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLLLHHHL                                         220-223                                                                              LLHLHHLH                                                                               LLHLHHHH                                                                               LLHLLLLL                                                                               LLHLHHHH                                         224-227                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLH                                         228-231                                                                              LLHLLLLL                                                                               LLHLHHLH                                                                               LLHLLLLL                                                                               LLHHHHLH                                         232-235                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLLLL                                                                               LLHHHHHH                                         236-239                                                                              LLHLLHLL                                                                               LLHLLLLL                                                                               LLHLLLLH                                                                               LLHHHHLL                                         240-243                                                                              LLHLLLLL                                                                               LLHLLLLL                                                                               LLHLLHLL                                                                               LLHHHHHH                                         244-247                                                                              LLHLLHLL                                                                               LLHHHHHH                                                                               LLHLLLLL                                                                               LLHHHHHH                                         248-251                                                                              LLHLLHLL                                                                               LLHLLHLL                                                                               LLHLHHLH                                                                               LLHHHHHH                                         252-255                                                                              LLHLLLLL                                                                               LLHLLHLL                                                                               LLHLLHLL                                                                               HHHHHHHH                                         0- 3  LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                         4-7   HHLLHHLL                                                                               LLLLHHLL                                                                               LHLLHLLL                                                                               LHLLHHHH                                          8-11 LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               HHLLLLLL                                         12-15 LHLLLLLL                                                                               LHLLHHLL                                                                               LHLLHHHL                                                                               LHLLLLLL                                         16-19 HHLLLLLL                                                                               LHLLLLLL                                                                               LHLHLLLL                                                                               HHLLHHLL                                         20-23 LHLLLLLL                                                                               HHLLHHLL                                                                               HHLLLLHH                                                                               LHLLLLLL                                         24-27 HHLLHHLL                                                                               HHLLHHLL                                                                               LHLHHHLL                                                                               HHLLHHLL                                         28-31 LHLLHHLL                                                                               LHLLHHLL                                                                               HHLLHHLL                                                                               LHLHHHLL                                         32-35 LHHLLLLL                                                                               LHLLLLLL                                                                               HHLLLLHH                                                                               HHLLLLLL                                         36-39 HHLLLLLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHLHHHLL                                         40-43 LHHLLLLL                                                                               LHLLLLLL                                                                               HHLLLLLL                                                                               LHLLLLLL                                         44-47 LHLHHHLL                                                                               LHLLLLLL                                                                               LHLLHHHL                                                                               LHLHHHLL                                         48-51 LHLLLLLL                                                                               LHLLHHLL                                                                               LHLLLLLL                                                                               HHLLHHLL                                         52-55 LLLLLLLL                                                                               HHLLLLLL                                                                               HLLLLLLL                                                                               HHLLLLLL                                         56-59 LHLLLLLL                                                                               LLLLLLLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                         60-63 HHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHHLHHLL                                         64-67 HHLHHHLL                                                                               HHLHHHLL                                                                               LHLHHHLL                                                                               LHLHHHLL                                         68-71 HHLHHHLL                                                                               LHLHHHLL                                                                               HHLHHHLL                                                                               LHLHHHLL                                         72-75 HHLHHHLL                                                                               LHLHHHLL                                                                               HHLHHHLL                                                                               LHLHHHLL                                         76-79 HHLHHHLL                                                                               LHLHHHLL                                                                               HHLHHHLL                                                                               LHLHHHLL                                         80-83 HHLLHHHH                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               HHLLHHLL                                         84-87 LHLLHHLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               HHLLHHLL                                         88-91 LHLLHHLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               HHLLHHLL                                         92-95 LHLLLLLL                                                                               HHLLHHLL                                                                               LHLLHHLH                                                                               HHLLHHLL                                         96-99 HHLLHHLL                                                                               LHLLHHLL                                                                               LHLHHHLL                                                                               LHLLLLLL                                         100-103                                                                              HHLHHHLL                                                                               LHLLHHLL                                                                               LHLLLLLL                                                                               LHLHLLLL                                         104-107                                                                              LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLLLLL                                         108-111                                                                              LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHHL                                                                               LHLLHHHL                                         112-115                                                                              HHLLHHLL                                                                               HHLLHHLL                                                                               LHLLHHHH                                                                               LHLLHHHH                                         116-119                                                                              LHLLHHHH                                                                               LHLLHHHH                                                                               LHLLHHHH                                                                               LHLLHHHH                                         120-123                                                                              LHLLHHHH                                                                               LHLLHHHH                                                                               HHLLHHLL                                                                               HHLLHHLL                                         124-127                                                                              HHLLHHLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                         128-131                                                                              LHLLLLLL                                                                               LHLLHHLL                                                                               HHLLHHHH                                                                               LHLLHHHH                                         132-135                                                                              HHLLHHLL                                                                               LHLLLLLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                         136-139                                                                              HHLLHHLL                                                                               HHLLHHLL                                                                               LHLLLLLL                                                                               LHLLHHHH                                         140-143                                                                              LHLLHHLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                         144-147                                                                              LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                         148-151                                                                              LLLLHHLL                                                                               LHLLLLLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                         152-155                                                                              HHLLHHLL                                                                               LHLLHHLL                                                                               LHHLHHLL                                                                               LHLLLLLL                                         156-159                                                                              HHLLHHLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               LLLLLLLL                                         160-163                                                                              LHLLLLLL                                                                               LHLLHHLL                                                                               HHLLLLLL                                                                               LLLLLLLL                                         164-167                                                                              LHLLHHLL                                                                               HHLLLLLL                                                                               LHLLLLLL                                                                               LHLLLLLL                                         168-171                                                                              HHLLHHHL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               HHLLHHLL                                         172-175                                                                              LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHLLL                                                                               LLLLHHLH                                         176-179                                                                              LHLLLLLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                         180-183                                                                              LHLLHHLL                                                                               HHLLHHLL                                                                               LHLHHLLL                                                                               LHLLHHLL                                         184-187                                                                              LHLLHHLL                                                                               HHLHHLLL                                                                               HHLLHHLL                                                                               HHLLHHLL                                         188-191                                                                              HHLLHHLL                                                                               HLLLHHLL                                                                               LHLLLHHL                                                                               HHLLHHLL                                         192-195                                                                              LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                         196-199                                                                              LHLHHHLL                                                                               LLHHHLLL                                                                               HHLLHHLL                                                                               LHHHHHLL                                         200-203                                                                              HHLLHHLL                                                                               LHLLHHLL                                                                               HHLLHHLL                                                                               LHHHHHLL                                         204-207                                                                              HHHHLHHL                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               LHLLLHHL                                         208-211                                                                              HHHLHHLL                                                                               LHLLHHLL                                                                               LHLLHHLL                                                                               LHHHHHLL                                         212-215                                                                              LHLLHHLL                                                                               HHLLHHLL                                                                               LHLLHHLL                                                                               LHLLLLLL                                         216-219                                                                              HHLLHHLL                                                                               LLHHLLHH                                                                               LHHHLLLH                                                                               LHLLLLLL                                         220-223                                                                              LHHLLLLL                                                                               LLHHLLHL                                                                               LHLHLHHL                                                                               LHHHLLLL                                         224-227                                                                              HHHHHLLL                                                                               HHHHHHHH                                                                               LHLLHHLL                                                                               LHLLHHLL                                         228-231                                                                              HHHHHHLL                                                                               LHLLHHHL                                                                               LHLLHHLL                                                                               HHHHHHLL                                         232-235                                                                              HHHHHHHH                                                                               HHHHHHLL                                                                               LHLHHLLL                                                                               HHLLLHLL                                         236-239                                                                              HLLLLLLL                                                                               LHLLHLJL                                                                               HHHLLHLL                                                                               LHHHLHLH                                         240-243                                                                              HLHLHLHL                                                                               HLHLHLHL                                                                               HLHLHLHL                                                                               HLHLHLHL                                         244-247                                                                              HLHLHLHL                                                                               HLHLHLHL                                                                               HLHLHLHL                                                                               HLHLHLHL                                         248-251                                                                              HLHLHLHL                                                                               HLHLHLHL                                                                               HLHLHLHL                                                                               HLHLHLHL                                         252-255                                                                              HLLLHLHL                                                                               HLHLHLHL                                                                               HLHLHLHL                                                                               HLLLHLLL                                         0-3   HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                         4-7   HLHLLLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                          8-11 HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                         12-15 HLHHLLLL                                                                               HLHHLLLL                                                                               HHHHHLHH                                                                               HLHHHLHL                                         16-19 HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHLLLLL                                         20-23 HLHHHLHL                                                                               HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHHHLL                                         24-27 HLHLLLLL                                                                               HLHLLLLL                                                                               HLHHLLLL                                                                               HLHLLLHH                                         28-31 HLHHHLLL                                                                               HLHHHLLH                                                                               HLHHLLLL                                                                               HLHHLLLL                                         32-35 HLHLHHLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHHLHH                                         36-39 HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                         40-43 HLHHHHLL                                                                               HLHHHLLL                                                                               HLHHHLHL                                                                               HLHHHLLL                                         44-47 HLHHLLLL                                                                               HLHHHLHL                                                                               HHHHHLHH                                                                               HLHHHHLL                                         48-51 HLHHHLLL                                                                               HLLHLLLL                                                                               HLHHHLHL                                                                               HLHHHLLL                                         52-55 HLHHHLHL                                                                               HLHHHLHL                                                                               HLHHHLHH                                                                               HLHHHLHH                                         56-59 HLHHHLHH                                                                               HLHHHLHH                                                                               HLHHLLLL                                                                               HLHHHLHL                                         60-63 HLHHHLLL                                                                               HLHHHLHL                                                                               LLHHHLLL                                                                               HLHHHLLL                                         64-67 HLHLLLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                         68-71 HLHLLLLL                                                                               HLHHHLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                         72-75 HLHHLLLL                                                                               HLHHHLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                         76-79 HLHLLLLL                                                                               HLHHHLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                         80-83 HLHHLLLL                                                                               HLHLLLLL                                                                               HLHHHHLL                                                                               HLHHLLLH                                         84-87 HLHHHLLL                                                                               HLHLLLLL                                                                               HLLHHHLL                                                                               HLHLLLLL                                         88-91 HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                                                               HLHLLLLL                                         92-95 HLHHHLHL                                                                               HLHLLLLL                                                                               HHHHHLHH                                                                               HLHLLLLL                                         96-99 HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                         100-103                                                                              HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                         104-107                                                                              HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                         108-111                                                                              HLHHLLLL                                                                               HHHHHLLL                                                                               HHHHHHLL                                                                               HLHHHHLL                                         112-115                                                                              HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                         116-119                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                         120-128                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHLLLLL                                                                               HLHLLLLL                                         124-127                                                                              HLHLLLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                         128-131                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                         132-135                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHLLLLL                                                                               HLHHLLLL                                         136-139                                                                              HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                         140-143                                                                              HLHHLLLL                                                                               HLHHHLLL                                                                               HLLHLLLL                                                                               HLHHHLLL                                         144-147                                                                              HLHHHHLL                                                                               HLHHHLLL                                                                               HLLHLLLL                                                                               HLHHLLLL                                         148-151                                                                              HLHHHLLL                                                                               HLHHHLLL                                                                               HLHLLLLL                                                                               HHHHHHLL                                         152-155                                                                              HLLHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                         156-159                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLHL                                         160-163                                                                              HLHHHLHL                                                                               HLHHHLLL                                                                               HLHHHLLH                                                                               HLHHHLLH                                         164-167                                                                              HLHHHLHL                                                                               HLHHHLLH                                                                               HLHHHLLH                                                                               HLHHHLLH                                         168-171                                                                              HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                         172-175                                                                              HLHHHLLL                                                                               HLHHHHLL                                                                               HLHHHLLL                                                                               HHHHHLLL                                         176-179                                                                              HLHHLLLL                                                                               HHHLHLLL                                                                               HLHHHLHH                                                                               HLHHLLLL                                         180-183                                                                              HLHHLLLL                                                                               HLHHHLLL                                                                               HHHHHHLL                                                                               HLHHHLLL                                         184-187                                                                              HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHHLL                                         188-191                                                                              HLHHHLLL                                                                               HLHHHLLL                                                                               HHHHHHLL                                                                               HLHLLLLL                                         192-195                                                                              HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                         196-199                                                                              HLHHHLLL                                                                               LLHHLLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                         200-203                                                                              LLHHLLLL                                                                               HLHHHLLL                                                                               HLHLLLLL                                                                               HLHHHLLL                                         204-207                                                                              HLHHHHLL                                                                               HLHHHLLL                                                                               HLHHHHLL                                                                               HHHHHLLL                                         208-211                                                                              HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                         212-215                                                                              HLHHLLLL                                                                               HLLHLLLL                                                                               HLHLHLLL                                                                               HLHHHLLL                                         216-219                                                                              HLHHLLLL                                                                               LLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLHL                                         2201∝223                                                                      HLHHHLLL                                                                               HLHHHLLL                                                                               HHHHHLHH                                                                               HLHHHLHL                                         224-227                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                         226-231                                                                              HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                         232-235                                                                              HLHHHLLL                                                                               HLHLHLLL                                                                               HLHHHLLL                                                                               HLHHHHLL                                         236-239                                                                              HLHHHLLL                                                                               HLHHHLLH                                                                               HLHHLLLL                                                                               HLHHLLLL                                         240-243                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHHLLL                                         244-247                                                                              HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                         248-251                                                                              HLHHHLLL                                                                               HLHHHLLL                                                                               HLHHLLLL                                                                               HLHHHLLH                                         252-255                                                                              HLHHLLLL                                                                               HLHHLLLL                                                                               HLHHLLLL                                                                               HLLHLLLL                                         0-3   LLLLLLLH                                                                               LLHHLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         4-7   LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLHHLH                                                                               LLHHLLLH                                          8-11 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         12-15 LLLLLLLH                                                                               LLLLLLLH                                                                               HLLLHHLH                                                                               HHLLLLLH                                         16-19 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         20- 23                                                                               LHLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         24-27 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         28-31 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         32-35 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LHLLLLLH                                         36-39 LLLLLLLH                                                                               LLHHLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         40-43 LLLLLLLH                                                                               LLLLLLLH                                                                               HHLLLLLH                                                                               LLLLLLLH                                         44-47 LLLLLLLH                                                                               HHLLLLLH                                                                               HLLLLLHH                                                                               LLLLLLLH                                         48-51 LLLLLLLH                                                                               LLLLLLLH                                                                               HHLLLLLH                                                                               LLLLLLLH                                         52-55 HHLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                         56-59 LHLLLLLH                                                                               LHLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         60-63 LLLLLLLH                                                                               HHLLLLLH                                                                               LLHHLLLH                                                                               LLLLLLLH                                         64-67 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         68-71 LLLLLLLH                                                                               LLHHLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         72-75 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         76-79 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         80-83 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         84-87 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         88-91 LHLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         92-95 HHLLLLLH                                                                               LLLLLLLH                                                                               HLLLLLLH                                                                               LLLLLLLH                                         96-99 LLLLLLLH                                                                               LLLLLLLH                                                                               LLHHLLLH                                                                               LLLLLLLH                                         100-103                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         104-107                                                                              LLLLLLLH                                                                               LLHHLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         108-111                                                                              LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLHLH                                                                               LLHHLHLH                                         112-115                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         116-119                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                         120-123                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         124-127                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         128-131                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         132-135                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         136-139                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         140-143                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         144-147                                                                              LLLLLLLH                                                                               HHLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         148-151                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               HLLLLLLH                                         152-155                                                                              LLHHLLLH                                                                               LHHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                         156-159                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               HLLLLLLH                                         160-163                                                                              HHLLLLLH                                                                               LLLLLLLH                                                                               LHLLLLLH                                                                               HLLLLLLH                                         164-167                                                                              LLLLLLLH                                                                               HLLLLLLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                         168-171                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         172-175                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         176-179                                                                              LLLLLLLH                                                                               LLHHLLLH                                                                               HHLLLLLH                                                                               LLLLLLLH                                         180-183                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         184-187                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         188-191                                                                              LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHHLHH                                                                               LLHHLLLH                                         192-195                                                                              LLHHLLLH                                                                               HLHHLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         196-199                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLHHHHH                                                                               LLLLLLLH                                         200-203                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         204-207                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLHLLH                                         208-211                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         212-215                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         216-219                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLHHLHHH                                                                               LHHHLLLH                                         220-223                                                                              LLHHLLLH                                                                               LLHHLLLH                                                                               HLLLLLLH                                                                               HHLLLLLH                                         224-227                                                                              LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                         228-231                                                                              LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                         232-235                                                                              LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                         236-239                                                                              LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                                                               LLHHLLLH                                         240-243                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         244-247                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         248-251                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               HHLLLLLH                                         252-255                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLHHLLLH                                                                               LHLLLLLH                                         0-3   HHLLLLLH                                                                               HHLLLLLH                                                                               LHLLHLLL                                                                               LHLLHLHH                                         4-7   HHLHLLHH                                                                               LHLLHHLH                                                                               LHLLLHHL                                                                               LHLLLLLH                                          8-11 LHHLLHLH                                                                               LHHLLHLH                                                                               LHHLLHLH                                                                               LHHLLLLH                                         12-15 LHHLLLLH                                                                               LHHLLHLH                                                                               LHLLLLHL                                                                               LLLLLLLH                                         16-19 LHHLLLLH                                                                               LHHLLLLH                                                                               LHLLLLLH                                                                               HHLLLLLH                                         20-23 LHLLLLLH                                                                               HHLLLLLH                                                                               LHLHHHLH                                                                               HHLHHHLH                                         24-27 HHLLLLLH                                                                               LHLLHLLH                                                                               LHLLLLLH                                                                               HHLHLLHH                                         28-31 LLLLLLLH                                                                               LHLHLHLH                                                                               HHLLLLLH                                                                               HHLLLLLH                                         32-35 HHLLLLLH                                                                               LHHLLLLH                                                                               LHHLHHHH                                                                               LLLLLLLH                                         36-39 LHHLLLLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                                                               HHLLLLLH                                         40-43 HHLLLLLH                                                                               LHHLLLLH                                                                               LLLLLLLH                                                                               LHHLLLLH                                         44-47 HHLLLLLH                                                                               LLLLLLLH                                                                               LHLLLLHL                                                                               HHLHHHLH                                         48-51 LHHLLLLH                                                                               HHLHLLHH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         52-55 LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         56-59 LLLHHLHH                                                                               LLLHHLHH                                                                               LHLLLLLH                                                                               LHHLLLLH                                         60-63 LLLLLLLH                                                                               LHLLHHHL                                                                               LHLLLHLL                                                                               LHLLLLLH                                         64-67 HHLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                         68-71 HHLLLLLH                                                                               LHLHHLHL                                                                               HHLLLLLH                                                                               LHLLLLLH                                         72-75 HHLLLLLH                                                                               LHLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                         76-79 HHLLLLLH                                                                               LHLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                         80-83 LHLLLLLL                                                                               HHLLLLLH                                                                               LLLLLLLH                                                                               LHLLLLLH                                         84-87 LHHHLLLH                                                                               HHLLLLLH                                                                               HHHLLLLH                                                                               HHLLLLLH                                         88-91 HHLHLLHH                                                                               HHLLLLLH                                                                               LHLLLLLH                                                                               HHLLLLLH                                         92-95 LLLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLHL                                                                               HHLLLLLH                                         96-99 HHLHHLHH                                                                               HHHLLLLH                                                                               LHLLLHHH                                                                               HHHLLLLH                                         100-103                                                                              HHLLLLLH                                                                               HHHLLLLH                                                                               LHHLLLLH                                                                               LHHLLLLH                                         104-107                                                                              HHHLLLLH                                                                               LHLLHHLL                                                                               HHHLLLLH                                                                               LHHLLLLH                                         108-111                                                                              LHLHHLHL                                                                               LHLLLLLH                                                                               LHLHHLLL                                                                               LHLHHLLL                                         112-115                                                                              HHLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                                                               HHLLLLLH                                         116-119                                                                              LHLLLLLH                                                                               HHLLLLLH                                                                               LHLHLLLH                                                                               HHLHLLLH                                         120-123                                                                              LHLLLLLH                                                                               HHLLLLLH                                                                               HHLLLLLH                                                                               HHLLLLLH                                         124-127                                                                              HHLLLLLH                                                                               HHLLLLLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         128-131                                                                              LHHLLLLH                                                                               HHHLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                         132-135                                                                              LLLLLLLH                                                                               LHLLLLLH                                                                               HHLLLLLH                                                                               HHHLLLLH                                         136-139                                                                              HHHLLLLH                                                                               LLLLLLLH                                                                               LHHLLLLH                                                                               LHLLLLLH                                         140-143                                                                              HHLLLLLH                                                                               LLLLLLLH                                                                               HHLHLLHH                                                                               LLLLLLLH                                         144-147                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               HHLHLLHH                                                                               HHHLLLLH                                         148-151                                                                              LLLLLLLH                                                                               LHLLLLLH                                                                               HHLHLLHH                                                                               LLLLLLHL                                         152-155                                                                              LHHLLLLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                                                               LLLLLLLH                                         156-159                                                                              LLLLLLLH                                                                               HHHLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                         160-163                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LLLHHLHH                                                                               LLLHHLHH                                         164-167                                                                              LHLLLLLH                                                                               LLLHHLHH                                                                               LLLHHLHH                                                                               LLLHHLHH                                         168-171                                                                              LHLLLLLH                                                                               LHLLHHLH                                                                               LLLLLLLH                                                                               LLLLLLLH                                         172-175                                                                              LHLLLLLH                                                                               LLLLLLLH                                                                               LHLLLLLH                                                                               LHLLLLHL                                         176-179                                                                              LHLLLLLH                                                                               LHLHLLHH                                                                               LLLLHLHH                                                                               HHLLLLLH                                         180-183                                                                              HHHLLLLH                                                                               LLLLLLLH                                                                               HHLLLLHL                                                                               LHLLLLHH                                         184-187                                                                              HHLLLLLH                                                                               HHHLLLLH                                                                               HHLLLLLH                                                                               LLLHLHHL                                         188-191                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               LHLLLLHL                                                                               HHLHLLHH                                         192-195                                                                              HHLLLLLH                                                                               LHLHHHLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                         196-199                                                                              LHLLLLLH                                                                               LHLLLLLH                                                                               HHLHLLHH                                                                               LHLLLLLH                                         200-203                                                                              LHLLLLLH                                                                               LHLLLLLH                                                                               HHLHLLHH                                                                               LHLHLLHH                                         204-207                                                                              HHLLLLLH                                                                               LHLLHHLH                                                                               LLLLLLLH                                                                               LHLLLLHL                                         208-211                                                                              LHLLLLLH                                                                               LHLLHLHL                                                                               LHLLLLLH                                                                               LHLLHLHH                                         212-215                                                                              HHLHLLHH                                                                               HHLHLLHH                                                                               LHLHLLLL                                                                               HHLLLLLH                                         216-219                                                                              HHLLLLLH                                                                               LHHLLLLH                                                                               LHHLLHLH                                                                               LLLLLLLH                                         220-223                                                                              LHLLLLLH                                                                               LLLHLLHH                                                                               LHLLLLHL                                                                               LLLLLLLH                                         224-227                                                                              HHLLLLLH                                                                               LHLLLLLH                                                                               LLLLLLLH                                                                               HHLLLLLH                                         228-231                                                                              HHLLLLLH                                                                               LLLLLLLH                                                                               HHLLLLLH                                                                               LLLLLLLH                                         232-235                                                                              HHLLLLLH                                                                               LLLLLLLH                                                                               HHLLLLLH                                                                               LLLLLLLH                                         236-239                                                                              HHHHLLHL                                                                               LHLHLHLH                                                                               LHLLLLLH                                                                               HHLLLLHH                                         240-243                                                                              HHLLLLLH                                                                               HHHLLLLH                                                                               HHHLLLLH                                                                               LLLLLLLH                                         244-247                                                                              LLLLLLLH                                                                               HHLLLLLH                                                                               HHHLLLLH                                                                               LLHLLLLH                                         248-251                                                                              LLLLLLLH                                                                               LLLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                         252-255                                                                              HHHLLLLH                                                                               HHHLLLLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                         0-3   HHLLHLHL                                                                               HHLLLLLH                                                                               LHLLLLLL                                                                               LHHHLHLL                                         4-7   LHLLHLLL                                                                               HLHLHLHH                                                                               HHLLLLLH                                                                               HHHHHHHH                                          8-   LHLLLLHH                                                                               LHLLHLHH                                                                               LHLHLHHH                                                                               HHLLLLLL                                         12-15 HHLLLLLL                                                                               LHHHLHHH                                                                               HHLLLLHH                                                                               HHLLLLLH                                         16-19 HHHLLHHH                                                                               HHHLLHHH                                                                               HHHLHLLL                                                                               HHLLHHHH                                         20-23 HHHHLHHL                                                                               LHHHLHHL                                                                               LHHHLLHH                                                                               LHHLHLHL                                         24-27 HHLHLHLH                                                                               HLHHLLHL                                                                               HHLLLHHH                                                                               LHLLHLLL                                         28-31 HHLLLLLH                                                                               LHLHLHHL                                                                               HHHHLLHH                                                                               HHLLHLLL                                         32-35 HHLHLHLL                                                                               HHLLHLLL                                                                               LHLLLLLL                                                                               HHLLLLLH                                         36-37 HHLLLLLL                                                                               HHLLLLLL                                                                               HHLLLLLL                                                                               HHLLHLHL                                         40-43 HHLHLHLL                                                                               HHLLHLHL                                                                               HHLLLLLH                                                                               HHHLLLHH                                         44-47 HHLLHHLL                                                                               HHLLLLLH                                                                               HHLLHLHH                                                                               LHHLHHLH                                         48-51 HHLLHHLL                                                                               LHLLHLLL                                                                               HHLLLLLH                                                                               HHLLLLLH                                         52-55 HHLLLLLH                                                                               HHLLLLLH                                                                               HHLLLLLH                                                                               HHLLLLLH                                         56-59 HLLLLLLH                                                                               HLLLLLLH                                                                               HHLLLHH HHLLLLLH                                         60-63 HHLLLLLH                                                                               HHHLLHLH                                                                               HHLHHLHH                                                                               HHLLLLLH                                         64-67 HHHHLHLL                                                                               HHLLHHHL                                                                               HHHHHHLL                                                                               HHHHHHLH                                         68-71 HHHHHHHH                                                                               HHHLHHHH                                                                               HHHLLHHH                                                                               HHHLLHHH                                         72-75 HHLLHLLH                                                                               HHHLHLHL                                                                               HHHLHHHL                                                                               HHHLHHLH                                         76-79 HHLLLLHL                                                                               HHHLLLLH                                                                               HHHLLLHL                                                                               HHHLLLHL                                         80-83 HHLHLHLL                                                                               HHHLHHLL                                                                               HHHLLHLL                                                                               LHHLHHHL                                         84-87 HLLLLLLH                                                                               HHHHHHHH                                                                               HHLHLHHL                                                                               HHHLLHLL                                         88-91 LHLLHLLL                                                                               HHHLLLHL                                                                               HHLLLLLH                                                                               HHHLHHLH                                         92-95 HHLLLLLH                                                                               HHLLLLHH                                                                               HHLHLHHH                                                                               HHHLLLLH                                         96-99 LHLLLLLL                                                                               HHLHHLLL                                                                               HLLLLLLL                                                                               HHLHHLLL                                         100-103                                                                              HHLLLLLL                                                                               HHLHHLLH                                                                               HHLLLLLL                                                                               HHLLLLLL                                         104-107                                                                              HHLHHLLH                                                                               HHHHLLLL                                                                               HHLLLLLLL                                                                              HHLLLLLL                                         108-111                                                                              HHHHLHHH                                                                               HLLHHLHH                                                                               LHLHHLHH                                                                               LHLHHLHH                                         112-115                                                                              HHHHLLLH                                                                               HHHHLLLH                                                                               HHLLLLHH                                                                               HHLLLLHL                                         116-119                                                                              HHLLHLHH                                                                               HHLLLLHL                                                                               LHLHLHHH                                                                               LHLLLLHL                                         120-123                                                                              HHHHLHHH                                                                               HHLLLLHH                                                                               HHLLLHHL                                                                               HHLLLHHH                                         124-127                                                                              HHLLHLLH                                                                               HHLLHLHH                                                                               HHLLLLLH                                                                               HHLLLLLH                                         128-131                                                                              HHLLLLLL                                                                               HHHLLLL HHHHHHLH                                                                               HHHHLHHL                                         132-135                                                                              HHHLLLLH                                                                               HHLLLLLL                                                                               HHHHHLH HHLLLLLL                                         136-139                                                                              HHLLLLLL                                                                               HHHLLLHH                                                                               HHLLLLLL                                                                               HHHHHHHL                                         140-143                                                                              HHLLLLLL                                                                               HHHLLLHH                                                                               LHLLHLLL                                                                               HHLLLLLH                                         144-147                                                                              HHHLLHLL                                                                               HHHLLHLL                                                                               LHLLHLLL                                                                               HHLHHLLH                                         148-151                                                                              HHHLLHLH                                                                               HHHLLHLH                                                                               LHLLHLLL                                                                               HHHLLHLH                                         152-155                                                                              HHHHHLLH                                                                               HHHHHLHL                                                                               HHHHHLLH                                                                               HHHHHLHL                                         156-159                                                                              HHHLLHHH                                                                               HHLHHLLH                                                                               HHLHHLLH                                                                               HHLLLLLH                                         160-163                                                                              HHLLLLLH                                                                               HHLLLLLH                                                                               LHLLLLLH                                                                               LLLLLLLH                                         164-167                                                                              HHHHHHHL                                                                               LHLLLLLH                                                                               LHLLLLLH                                                                               LHLLLLLH                                         168-171                                                                              HHHLHLHL                                                                               LHLLLLLH                                                                               HHLLLLLH                                                                               HHHLHHLL                                         172-175                                                                              HHLLLLLL                                                                               HHHLHLHL                                                                               HHLLLLLH                                                                               HHHLHHHH                                         176-179                                                                              HHLLLLLL                                                                               LHHHLHLH                                                                               HLHLHHLL                                                                               HHLLHLLL                                         180-183                                                                              HHLHHLLH                                                                               HHHLHHHL                                                                               LHHLHHLH                                                                               LHLLLLLH                                         184-187                                                                              HHLHHLLH                                                                               HHLHHLLH                                                                               HHLLHLLL                                                                               LHHLHHHL                                         188-191                                                                              HHHHLHLH                                                                               HHHHLHLH                                                                               HHHLHHH LHLLHLLL                                         192-195                                                                              HHLHLHH LHHLLHLH                                                                               HHLLLLLLL                                                                              HHLLLLLL                                         196-199                                                                              HHHHLLLH                                                                               HHHHLLLH                                                                               LHLLHLLL                                                                               HHHHLLHL                                         200-203                                                                              HHHHLLHL                                                                               HLHHLLHL                                                                               LLLLHLLL                                                                               LHHHLLHL                                         204-207                                                                              HHHHLHLH                                                                               HLHHLLHH                                                                               HHHLHLLL                                                                               HHHHLLHL                                         208-211                                                                              HHLLLLLL                                                                               LHHHLHLL                                                                               HHLLLLLL                                                                               HLLLLLLH                                         212-215                                                                              LLLLHLLL                                                                               LHLLHLLL                                                                               HHLHLHLH                                                                               HLLHHLLL                                         216-219                                                                              HHHHLLHL                                                                               HHHHLHHH                                                                               HHLLHHHH                                                                               HHLLLLLH                                         220-223                                                                              HHHLLHHL                                                                               HHLLLLLH                                                                               HHHHLHHH                                                                               HHLLLLLH                                         224-227                                                                              HHHHHLLL                                                                               HHHHHLLL                                                                               HHHHLLLL                                                                               HHHHHLLL                                         228-231                                                                              HHHLLHHL                                                                               HHHHHLHH                                                                               HHHLLHHL                                                                               HHHHHLLH                                         232-236                                                                              HHHHLHHL                                                                               HHHHHLHH                                                                               HHHHLHHL                                                                               HHLLLLL                                          236-239                                                                              HHHHHLLL                                                                               LHHLHLHH                                                                               HHLHHLHL                                                                               LHLLHLLL                                         240-243                                                                              HHLLHLLL                                                                               LHLHHLLL                                                                               HHLLHLLL                                                                               HHHLLLLH                                         244-247                                                                              HHHHLHHL                                                                               HHLLHLLL                                                                               HHHLLLLL                                                                               LHHLLLLL                                         248-251                                                                              HHHHHHHL                                                                               HHHHLLLL                                                                               HHHLLLLL                                                                               HHLLLLLL                                         257-255                                                                              HHLHHLLL                                                                               HHHHHLLL                                                                               HHHLHHLL                                                                               HHHHHHLH                                         0-3   LLLLHHHH                                                                               HHLLHHHH                                                                               LHHHHHHH                                                                               LHLLHHHH                                         4-7   HLLLHHHH                                                                               HHLLHHHH                                                                               LHLLHHH HLLLHHHL                                          8-11 HLLLHHH HLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHLLH                                         12-15 LLLLHLLH                                                                               HLLLHHHH                                                                               HLHHHHHH                                                                               LLLLHHLLL                                        16-19 HHLLHHHH                                                                               HHLLHHLL                                                                               LLLLHHH LHLLHHLH                                         20-23 LLLLHHHH                                                                               HLLLHHHH                                                                               LHLLHHHH                                                                               LLLLHHHH                                         24-27 LLLLHHHH                                                                               HHHLLHHHH                                                                              LLLLHHHH                                                                               HLLLLHHH                                         28-31 LLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                                                               LHLLHHH                                          32-35 LLLLHHHH                                                                               HHLLHHHH                                                                               LLLLLHLH                                                                               LLLLHHHH                                         36-39 HLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LHLLHHH                                          40-43 LLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHLH                                                                               HHLLHHHH                                         44-47 LLLLHHHH                                                                               LLLLHHHH                                                                               HLLHHHH HLLLHHHH                                         48-51 HLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         52-55 LLLLHHHH                                                                               LLLLH HHH                                                                              LLLLHHHH                                                                               LLLLHHHH                                         56-59 LLLLHHHH                                                                               LLLLHHHH                                                                               LHLLHHHH                                                                               LLLLHHHH                                         60-63 LLLLHHHH                                                                               HLLLHHHH                                                                               LHHLHHHH                                                                               LLLLHHHH                                         64-67 HLLLHHHH                                                                               HHLLHHHH                                                                               HHLLHHHH                                                                               LLLLHHHH                                         68-71 LHLLHHHH                                                                               LLLHHHHH                                                                               LHLLHHHH                                                                               LLLLHHHH                                         72-75 LLLLHHHH                                                                               HHLLHHHH                                                                               LHLLHHHH                                                                               LHLLHHHH                                         76-79 HHLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LHLLHHHH                                         80-83 HLHLHHHH                                                                               LHLLHHHH                                                                               LLLLHHHH                                                                               LHLLHHHH                                         84-87 LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               HHLLHHHH                                         88-91 HLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         92-95 LLLLHHHH                                                                               LLLLHHHH                                                                               HLLLHHHH                                                                               HHLLHHHH                                         96-99 LLLLLLHH                                                                               LLLLHHHH                                                                               LLLLLHHH                                                                               HLLLHHHH                                         100-103                                                                              LLLLLHHH                                                                               LLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHLLH                                         104-107                                                                              HHLLHHHH                                                                               LLLHHLHH                                                                               LLLLHLLH                                                                               LLLLHLLH                                         108-111                                                                              LHLLHHHH                                                                               HHLLHHHH                                                                               LLHLHHHH                                                                               LLLLHHHH                                         112-115                                                                              LLLLHHHH                                                                               HHLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                         116-119                                                                              HLLLHHHH                                                                               LHLLHHHH                                                                               HLLLHHHH                                                                               HLLLHHHH                                         120-123                                                                              HLLLHHHH                                                                               LHLLHHHH                                                                               HLLLHHHH                                                                               HHLLHHHH                                         124-127                                                                              HHLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         128-131                                                                              LLLLHHHH                                                                               LLLLHHHH                                                                               HHLLHHHH                                                                               LLLLHHHH                                         132-135                                                                              LHLLHHHH                                                                               LLLLHLLH                                                                               HLLLHHHH                                                                               LLLLHHHH                                         136-139                                                                              LLLLHLLH                                                                               LLLLHHHH                                                                               HLLLHHHH                                                                               LHLLHHHH                                         140-143                                                                              LLLLHLLH                                                                               HLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                         144-147                                                                              LHLLHHHH                                                                               HLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                         148-151                                                                              HLLLHHHH                                                                               HHLLHHHH                                                                               HLLLHHHH                                                                               LHLHHHH                                          152-155                                                                              LHLLHHHH                                                                               LHLLHHHH                                                                               HHLLHHHH                                                                               HHLLHHHH                                         156-159                                                                              HLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         160-163                                                                              LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         164-167                                                                              HHLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         168-171                                                                              LHLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         172-175                                                                              LLLLHHHH                                                                               HLLLHHHH                                                                               LHLLHHHH                                                                               HLLHHHH                                          176-179                                                                              HLLLHHHH                                                                               LLLLHHHH                                                                               HHLLHHHH                                                                               LLLLHHHH                                         180-183                                                                              HHLLHHLH                                                                               LLLLHHHH                                                                               HLHHHHHH                                                                               LLLLHHHH                                         184-187                                                                              HHLLHLLL                                                                               HHLLHHHH                                                                               LLLLHHHH                                                                               HHHLHHHH                                         188-191                                                                              HHLLHHHH                                                                               HHLLHHHH                                                                               HLHHHHHH                                                                               HLLLHHHH                                         192-195                                                                              HHLLHHHH                                                                               LHLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         196-199                                                                              LHLLHHHH                                                                               HLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                         200-203                                                                              LHLLHHHH                                                                               HLLHHHHH                                                                               HLLLHHHH                                                                               HHLHHHHH                                         204-207                                                                              HLLLHHHH                                                                               HHLLHHHH                                                                               LHLLHHHH                                                                               LHLLHHHH                                         206-211                                                                              HLLLHHHH                                                                               HHHHHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         212-215                                                                              HLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                                                               HLLLLLLL                                         216-219                                                                              LHLLLHHH                                                                               HLLHHHH HLLLHHHH                                                                               LLLLHHHH                                         220-223                                                                              HLLLHHHH                                                                               LLLLHHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                         224-227                                                                              LHLLHHHH                                                                               HLLLHHHH                                                                               HHLLHHHH                                                                               HLLLHHHH                                         228-231                                                                              LLLLHHHH                                                                               HLLLHHHH                                                                               HLLHHHH HLLHHHH                                          231-235                                                                              LLLLHHHH                                                                               HLLLHHHH                                                                               HHHLHHHH                                                                               LLLLHHHH                                         236-239                                                                              LLLLHHHH                                                                               HLLLHHHH                                                                               HLLLHHHH                                                                               HLLLHHHH                                         240-243                                                                              LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LLHLLLLH                                         244-247                                                                              LHLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         248-251                                                                              HLLLHHHH                                                                               HLLLLHHH                                                                               LLLLHHHH                                                                               LLLLHHHH                                         252-255                                                                              HLLLHHHH                                                                               HLLLLHHH                                                                               HLLLHHHH                                                                               LLLLHHHH                                         __________________________________________________________________________

While all of the states in the control ROM 14 have been depicted in Table IV above, only a relatively small number are involved in carrying out the operations illustrated by the flow diagrams of FIGS. 7-9.

More particularly, as shown in FIG. 6, four bit lines 14a lead from ROM 14 to A multiplexer 46. Lines 14a thus apply the first four bits in each of the 256 control words in ROM 14 to A multiplexer 46. Three of the lines 14a are decoded in A multiplexer 46 to address a selected one of the eight inputs to the multiplexer. Multiplexer 46, in the embodiment here described, comprises a set of sixteen eight input multiplexer units of the type manufactured and sold by Texas Instruments Incorporated, Dallas, Tex. and identified as Data Selectors/Multiplexers SM74151A. Each such unit is provided with decoding logic to select one of eight inputs. The fourth of the lines 14a is an inhibit line. When the fourth line is in state to inhibit multiplexer 46, all of the 16 output lines are low or zero.

In a similar manner, three lines 14b extend to B multiplexer 53. Two of lines 14b are used to address the four inputs to B multiplexer 53. The third line is an inhibit line. B multiplexer 53 comprises a set of sixteen four input multiplexer units manufactured and sold by Texas Instruments Incorporated and identified as Data Selectors/Multiplexers SM74LS152.

From Table V the use of the control states stored in ROM 14 is specified. In Table V all ROM 14 data is shown true. However, in Table IV bits 1-4, 11, 18, 21, 22, 25, 27-29, 35, 36, 40, 42, 48, 49, 50 and 61-64 are noted in complemented states. Thus, references between Tables IV and V must take into account this difference in rotation.

                                      TABLE V                                      __________________________________________________________________________     BITS                                                                               1 2 3 4       MULTIPLEXER A                                                    0 0 0 0 (MEM) A Multiplexer                                                                             Memory Input Enabled                                  0 0 1 0 (REU) "          Memory Input Enabled                                                           (Reverse)                                             0 1 0 0 (ST)  "          Status Input Enabled                                  0 1 1 0 (EMUX)                                                                               "          E Multiplexer Input                                                            Enabled                                               1 0 0 0 (WA)  "          WA Input Enabled                                      1 0 1 0 (DMUX)                                                                               "          D Multiplexer Input                                                            Enabled                                               1 1 0 0 (URA) "          Utility Register A                                                             Input Enabled                                         1 1 1 0 (SDX2)                                                                               "          SDX2 Input Enabled                                    0 0 0 1 (ZERO)                                                                               "          Outputs All Zero                                      X X X 0 (INHLSA)                                                                             "          Inhibited                                             0 1 0 1 (X'02')                                                                              "          X'02' Output Generated                                1 0 0 1 (X'18')                                                                              "          X'18'Output Generated                                 1 1 0 1 (X'1A')                                                                              "          X'1A'  Output Generated                               0 0 1 1 (X'16')                                                                              "          X'16' Output Generated                            BITS                                                                               5 6 7         MULTIPLEXER B                                                    0 0 0 (WP)    B Multiplexer                                                                             Workspace Pointer Input                                                        Enabled                                               0 1 0 (URB)   "          Utility Register B Input                                                       Enabled                                               1 0 0 (MD)    "          Memory Data Input Enabled                             1 1 0 (PC)    "          Program Counter Input                                                          Enabled                                               0 X 1 (ZERO)  "          Force All Outputs to Zero                             X X 0 (INHMSB)                                                                               "          Inhibit Most Significant                                                       Bit                                                   1 X 1 (X'02') "          Enabled Generation of X'02'                       BIT 8                                                                              0 (OX2)   Multiplexer D                                                                             DX2 Input Enabled                                         1 (SX2)   "          SX2 Input Enabled                                         0 (DX4)+X'40'                                                                            Multiplexer E                                                                             (DX4)+X'40' Input Enabled                                 1 TRAP    "          TRAP Input Enabled                                    BIT (ENCMDREV)                                                                               Enable Memory Data Reverse                                       BIT 10                                                                             (ENAREV)  Enable Reverse                                                   BIT 11                                                                             (INHMSBLSA)                                                                              Inhibit Most Significant Bit of LSA                              BIT 12                                                                             (ENALUBYTE)                                                                              Enable ALU Byte                                                  BIT 13                                                                             ALU to M Input Line                                                        BIT 14                                                                             ALU to S3 Input Line                                                       BIT 15                                                                             ALU to S2 Input Line                                                       BIT 16                                                                             ALU to S1 Input Line                                                       BIT 17                                                                             ALU to S0 Input Line                                                       BIT 18                                                                             ALU Carry In Enabled                                                       BIT 19                                                                             (ENWPLD) WP Register 40 Load Enabled                                       BIT 20                                                                             (ENMDLD) Memory Data Register Load Enabled                                 BITS                                                                               21                                                                               22                                                                               UTILITY REGISTER A j - 0 0                                                 0 1 Utility Register A Left Shield Enabled                                     1 0 Utility Register A Right Shift Enabled                                     1 1 Utility Register A Load Enabled                                        BITS                                                                               23                                                                               24                                                                               UTILITY REGISTER B                                                         0 0                                                                            0 1 Utility Register B Left Shift Enabled                                      1 0 Utility Register B Right Shift Enabled                                     1 1 Utility Register B Load Enabled                                        BIT 25                                                                             (ENCRUFF) CRU 24 Flip-Flop Enabled                                         BIT 26                                                                             (ENSCINC) Enable Shift Counter Increment                                   BIT 27                                                                             (ENPCLD)  Program Counter 42 Load Enabled                                  BIT 28                                                                             (ENPCINC) Program Counter 42 Increment Enabled                             BIT 29                                                                             (ENADCLD) Memory Register 56 Load Enabled                                  BIT 30                                                                             (ENADCINC)                                                                               Memory Register 56 Increment Enabled                             BITS                                                                               31                                                                               32                                                                               33                                                                               34 STATUS REGISTER                                                       0 0 0 0                                                                        0 0 0 1  Status Register Load Enabled                                          0 0 1 0                                                                        0 0 1 1                                                                        0 1 0 0                                                                        0 1 0 1                                                                        0 1 1 0                                                                        0 1 1 1                                                                        1 0 0 0                                                                        1 0 0 1                                                                        1 0 1 0                                                                        1 0 1 1                                                                        1 1 0 0                                                                        1 1 0 1                                                                        1 1 1 0                                                                        1 1 1 1                                                                    BIT 35 --                                                                      BIT 36 --                                                                      BITS                                                                               37                                                                               38                                                                               39                                                                               UTILITY REGISTER 13 SHIFT INPUT SELECT                                   0 0 0 URB 15 → URBO                                                     0 0 1 CR BIT IN                                                                0 1 0 URA 15                                                                   0 1 1 URB 00                                                                   1 0 0 0                                                                        1 0 1 1                                                                        1 1 0 CRUOUT                                                                   1 1 1 IR07                                                                 BIT 40                                                                             --                                                                         BIT 41                                                                             Enable Fetch                                                               BIT 42                                                                             Enable Store                                                               BIT 43                                                                             Enable Delay                                                               BITS                                                                               44                                                                               45                                                                               46                                                                                 47                                                                             48                                                                               49                                                                               50                                                                               DECISION & SPECIAL CONTROL                                       1 0 0 1 0 1 0 Enable End of Instruction                                                      (EOI)                                                            0 0 0 0 1 0 0 RESTART                                                      BITS 51 - 58                                                                           J0                                                                     BITS 59 - 60                                                                           J1                                                                     BITS 61 - 63                                                                           NRA                                                                    __________________________________________________________________________

From Table V it will be seen that ROM 14 bits 1-3 are decoded in A multiplexer 46 to address its eight inputs. The ROM bits 1-4 are employed in combination to provide 14 functions, including controls for generating the indexing conditions employed for locating the workspace pointer, the program counter and the status register at the desired last three elements of the workspace.

Bits 5, 6 and 7 are employed by B multiplexer 53 to address the four inputs thereto, the first two control inputs of B multiplexer 46 being decoded and the third an inhibit line.

By way of relating the contents thus far described of Table V to the contents of Table IV and to the flow diagram of FIGS. 7-9, note the following: In FIG. 7, state 00 requires A multiplexer 46 to address E multiplexer 46a. In Table V it will be noted that A multiplexer 46 enables the E multiplexer input when the first four bits have the states 0110. In Table IV, the ROM bits 1-4 are the first four bits found at the top of column 1. Their states are designated by the legend HLLH, i.e., high, low, low, high. Since as above indicated, the first four ROM bits in Table IV are shown completed, the legend HLLH thus corresponds with the complement of 0110. Thus, for every function indicated in the flow diagrams of FIGS. 7-9, Table V gives the state and the element affected. From Table V the key to the precise bits in ROM 14 which are utilized for carrying out the function designated in the flow diagrams are specified. Since there are 64 bits to each word in ROM 14, many of which are utilized for various computer functions not mentioned in the flow chart of FIGS. 7-9, their function has been omitted from Table V.

The TILINE bus above described is preferably of the type described and claimed in U.S. Ser. No. 407,761, now U.S. Pat. No. 3,886,524 by Daren R. Appelt and entitled Asynchronous Communication Bus.

Having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art and it is intended to cover such modifications as fall within the scope of the appended claims. 

What is claimed is:
 1. A high speed context switching computer having a memory comprising:a. a multi-bit multi-function arithmetic unit having two inputs and an output; b. a workspace pointer register, a program counter register and a status register containing the address of the first element of a first workspace in memory of a problem program, the address of the current instruction in the problem program and the status of the problem program, respectively; c. a first and second multiplexer each having its output connected to a respective one of the inputs of the arithmetic unit, the workspace pointer register and the program counter register each being connected at their outputs to the inputs of one of the multiplexers, the input to the workspace pointer register being connected to the output of the memory and the input to the program counter register being connected to the output of the arithmetic unit; d. means connected to the memory and to the arithmetic unit for executing the problem program; e. control means having an interrupt signal input, said control means being connected to the means for executing and he arithmetic unit, operable upon occurrence of an interrupt signal, for stopping the problem program and for performing an interrupt program, said control means including means for storing in elements of a second workspace located at addresses in memory a predetermined number of locations from the absolute address of the first element thereof, the contents of the registers at the instant of the occurrence of the interrupt signal; and f. control means operable upon completion of the interrupt program to return to the registers the contents of the predetermined elements for resumption of execution of the problem program at the point therein at which the interrupt signal occured.
 2. The combination of claim 1 in which said status register is connected at the output to one of said multiplexers and at its input to a memory channel.
 3. The combination set forth in claim 1 in which said workspace pointer register and said program counter register are connected at their outputs to inputs of one of said multiplexers and said status register is connected at its output to one input of the other of said multiplexers and wherein the output of said arithmetic unit is connected to the input of said program counter register and the inputs of said workspace pointer register and said status register are connected to a memory channel.
 4. A digital computer system having a main memory for reading and writing binary elements representing data, instructions and addresses, and for forming therein a first plurality of elements representing at least one problem program and problem workspace, and a second plurality of elements representing at least one interrupt program and interrupt workspace, comprising:a. a workspace pointer register for storing an absolute workspace pointer address identifying the location in the memory of the problem workspace or the interrupt workspace; b. means for executing the problem program and the interrupt program; c. an interrupt signal input circuit for receiving an interrupt signal during the execution of the problem program to cause the means for executing to shift to execution of an interrupt program; d. automatic storing means, responsive to the interrupt signal, for storing the contents of the workspace pointer register, representative of the problem workspace pointer address at a prescribed location within the interrupt workspace a prescribed number of locations from the absolute interrupt workspace pointer address; e. automatic loading means for loading the workspace pointer register with the interrupt workspace pointer address; and f. automatic restoring means responsive to the means for executing for restoring the problem workspace pointer address into the workspace pointer register when the interrupt program has been executed.
 5. The computer system of claim 4 further comprising a program counter for storing the address of the current instruction being executed during either the problem program or the interrupt program, wherein the automatic storing means further comprise means for storing the contents of the program counter register containing the address of the next instruction of the problem program at a second prescribed location relative to the interrupt workspace pointer address, wherein the automatic loading means further comprise means for loading the program counter register with the address of the first instruction of the interrupt program, and wherein automatic restoring means further include means for inserting the next instruction of the problem program back into the program counter register upon conclusion of the interrupt program.
 6. The computer system of claim 44 wherein the automatic storing means further comprise:(c) (i) an adder having a first input for receiving the absolute address of the problem workspace pointer address and a second input for receiving the address relative to the workspace pointer address, for summing the aboslute and relative addresses to provide an ultimate address at an output; and (ii) a memory address register, having an input connected to the output of the adder and an output connected to the memory for addressing the memory with the ultimate address from the adder.
 7. The computer system of claim 5 wherein the automatic storing means further comprise:(c) (i) an adder having a first input for receiving the aboslute address of the problem workspace pointer address and a second input for receiving the address relative to the workspace pointer address, for summing the absolute and relative addresses to provide an ultimate address at an output; and (ii) a memory address register having an input connected to the output of the adder and an output connected to the memory for addressing the memory with the ultimate address from the adder. 